Friction materials used as brake linings, disc brake pads, clutch facings and brake blocks are usually made from asbestos, organic friction modifiers and abrasive particles which are held together by a resin matrix. Such friction materials can have poor friction stability under varying temperature conditions. Since disc brake pads receive more thermal energy per surface area, it is necessary to modify the friction formula to provide an inherent thermal stability in order to prevent rapid wear and reduction of friction coefficient.
In an attempt to reduce the thermal energy in the disc pads, the rotors used in conjunction with the disc pads were redesigned to be made of a copper base material. Copper rotors have the ability to dissipate the thermal energy and thereby to reduce the wear rate. However, the abrasive particles currently used in the disc pad tend to score the copper base rotor.
In another attempt to provide frictional stability, a known prior art disclosure teaches that metal sulfide when added to a brake lining composition in place of the resin binder will reduce wear. However, the curing process required to convert the metal sulfide into a matrix binder requires pressures from 2 to 20 tons/in..sup.2 and temperatures from 572.degree. to 1112.degree. F. Therefore, such materials have not gained wide spread acceptance by the brake lining producers.